I have a 2007 RX350 that the tire pressure warning light came on last night. I checked the pressure in all the tires and found one to be at 23.5 PSI with the others at approx. 28 PSI. I aired up the tire to 31 PSI and the warning light went off. This morning I checked the tire and the pressure had dropped to 30PSI. I took it to the Lexus dealer today and they checked the tire. At first they said they couldn't find a problem and came back to verify that they were looking at the correct tire. Then they later came back and said that there wasn't a good seal between the tire and the wheel and that was causing a slow leak. This seems odd to me since these are tires that were put on in July of this year and I did not have a problem with the warning light coming on before. Then about an hour after I got back from the dealership I went out to my car and the warning light was on again. I called the dealership back and they instructed me to inflate all the tires to 34 PSI (since the weather has turned colder) and see if the light went off. I made the adjustment to all the tires but the warning light is still on. I am taking the car back to the dealership tomorrow.

Has anyone had any similar problem or does anyone have any ideas as to what might be the problem? I feel like the dealership is taking stabs in the dark.

 

Check the spare tire, it is usually the one that is under-inflated (all tires including the spare have sensors).

 

Welcome to Club Lexus, lexusride.

Listen to Rainbird. Everyone forgets about the spare, including the dealerships.

 

pm sent follow those directions

 

The warning light went out yesterday after I added air to the one tire in question. It seems like if the problem wasn't related to that tire the warning light wouldn't have gone off, right?

I did check the spare tire and it is at 28 PSI. Would that cause the warning light to come on?

 

Yes add air to the spare. I add extra (35 psi) just so I don't have to mess with it.

 

But if the warning light went out after I added air to the tire in question doesn't that mean that there is a problem with that tire? The spare tire was at the same PSI today as it was yesterday.

 

Probability so, I would have that tire checked out for sure. Maybe the tire shop where you had it installed. You are right at the pressure where the spare will trigger the light. Add the air to remove it from your troubleshooting.